BALTIMORE – Exposure to adalimumab was not associated with any specific pattern of minor or major birth defects in women with rheumatoid arthritis taking the biologic drug during pregnancy, according to preliminary data from an ongoing prospective cohort study.
Between November 2004 and January 2012, 312 pregnant women in the United States and Canada – 69 women with RA exposed to adalimumab, 80 women with RA who had not taken adalimumab, and 163 healthy controls – were enrolled before 20 weeks’ gestation. Their mean age was 32-33 years, and about two-thirds were white.
Major birth defects among the live births were identified in 5% of the babies born to women exposed to adalimumab, compared with about 4% among disease-matched controls who did not take adalimumab, and about 7% among healthy controls, Christina Chambers, Ph.D., of the University of California, San Diego, reported at the annual meeting of the Teratology Society.
The rate of minor structural abnormalities was similar in the three groups, at about 22%-24%, and there was no pattern of major or minor structural defects noted among the adalimumab-exposed group. (The three major malformations in the adalimumab-exposed group were one ventricular septal defect, one unilateral cryptorchidism, and one case of microcephaly.)
There were no stillbirths. The rate of spontaneous abortions was not significantly different between the three groups, nor were the rates of preterm delivery or birth weights, said Dr. Chambers, director of the California Teratogen Information Service and Clinical Research Program.
Through 1-year of follow-up, there were no malignancies among the infants and the rates of serious infections in the three groups were similar (about 3% in the two RA groups and 2% in the healthy comparison group).
The teratogenic effects of adalimumab, a tumor necrosis factor blocker, are being evaluated in the pregnancy registry, which is part of the Organization of Teratology Information Specialists (OTIS) Autoimmune Diseases in Pregnancy Project.
Adalimumab, marketed as Humira by Abbott Laboratories, was first approved in the United States in 2002 as a treatment for people with moderately to severely active RA, and has since been approved for other autoimmune diseases, including psoriatic arthritis, ankylosing spondylitis, Crohn’s disease, and psoriasis.
The registry study is comparing outcomes in women with RA who are treated with adalimumab during pregnancy, in women with RA not treated with adalimumab during pregnancy, and in women who do not have an autoimmune disease and have not been exposed to adalimumab or any known teratogenic drug during pregnancy. The study includes medical record reviews, examination of infants for major and minor structural abnormalities, and follow-up for 1 year post partum. It is expected to continue through 2017; the pregnant women are recruited from OTIS member services and from rheumatologists, and other clinicians who care for these patients.
Although little to no placental transfer of adalimumab is expected during early pregnancy, limited information on the safety of adalimumab during pregnancy has been published, Dr. Chambers said.
Abbott Laboratories is among the sponsors of the OTIS Autoimmune Diseases in Pregnancy Project, which is also evaluating safety of medications in women with ankylosing spondylitis, psoriasis and psoriatic arthritis, and Crohn’s disease. Dr. Chambers and her coauthors have received or receive grant funding for research on medications for autoimmune diseases from Abbott and other manufacturers: Amgen, Bristol Myers Squibb, Roche Genentech, Sanofi, Teva, Par, Sandoz, and Apotex.